Integration of the new analysis driver, behind a flag.

pkg/analyzer/lib/src/dart/analysis/driver.dart

Index: pkg/analyzer/lib/src/dart/analysis/driver.dart
diff --git a/pkg/analyzer/lib/src/dart/analysis/driver.dart b/pkg/analyzer/lib/src/dart/analysis/driver.dart
index 6677376eb6194c04a09169e52b31f29eb282102f..d7dc7c6969bb9dc3e5fdfef010607af56780c7d3 100644
--- a/pkg/analyzer/lib/src/dart/analysis/driver.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/driver.dart
@@ -70,6 +70,7 @@ import 'package:crypto/crypto.dart';
  * TODO(scheglov) Clean up the list of implicitly analyzed files.
  */
 class AnalysisDriver {
+  String name;
   final PerformanceLog _logger;
 
   /**
@@ -224,6 +225,7 @@ class AnalysisDriver {
     try {
       PerformanceLogSection analysisSection = null;
       while (true) {
+        await pumpEventQueue(100);

[Paul Berry, 2016/10/31 20:09:39]

Can you add a comment explaining why this is needed, and how the number 100 was
chosen?

[scheglov, 2016/10/31 20:37:11]

Done in https://codereview.chromium.org/2466713002

         await _hasWork.signal;
 
         if (analysisSection == null) {
@@ -707,6 +709,20 @@ class AnalysisDriver {
     set.remove(element);
     return element;
   }
+
+  /**
+   * Returns a [Future] that completes after pumping the event queue [times]
+   * times. By default, this should pump the event queue enough times to allow
+   * any code to run, as long as it's not waiting on some external event.
+   */
+  Future pumpEventQueue([int times = 5000]) {

[Paul Berry, 2016/10/31 20:09:38]

Can we make this private?  It seems hacky to use it in non-test code and I don't
want calls to it to proliferate without us thinking really hard about it.

+    if (times == 0) return new Future.value();
+    // We use a delayed future to allow microtask events to finish. The
+    // Future.value or Future() constructors use scheduleMicrotask themselves and
+    // would therefore not wait for microtask callbacks that are scheduled after
+    // invoking this method.
+    return new Future.delayed(Duration.ZERO, () => pumpEventQueue(times - 1));
+  }
 }
 
 /**